The iTunes Store's Power Search was one of the nice parts of iTunes that allowed you to set up all kinds of variables to find what you're looking for. In iTunes 11, the Power Search section disappeared, but writer Kirk McElhearn shows how to bring it back.

To get the Power Search option back, you can either click this link to immediately open it up in iTunes or use this AppleScript if you're on a Mac. From there, you can set all kinds of parameters for searches, including genres, movies for rental, and more.